# std::is_scoped_enum

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< cpp‎ | types

Defined in header `<type_traits>` |  |
template< class T > struct is_scoped_enum; |  | (since C++23)

`std::is_scoped_enum` is a UnaryTypeTrait.

Checks whether `T` is a scoped enumeration type. Provides the member constant `value` which is equal to true, if `T` is a scoped enumeration type. Otherwise, `value` is equal to false.

If the program adds specializations for `std::is_scoped_enum` or `std::is_scoped_enum_v`, the behavior is undefined.

### Template parameters

T | - | a type to check

### Helper variable template

template< class T > constexpr bool is_scoped_enum_v = is_scoped_enum<T>::value; |  | (since C++23)

## Inherited from std::integral_constant

### Member constants

value [static] | true if `T` is a scoped enumeration type, false otherwise (public static member constant)

### Member functions

operator bool | converts the object to bool, returns value (public member function)
operator() (C++14) | returns value (public member function)

### Member types

Type | Definition
`value_type` | bool
`type` | std::integral_constant<bool, value>

### Notes

Feature-test macro | Value | Std | Feature
--- | --- | --- | ---
`__cpp_lib_is_scoped_enum` | `202011L` | (C++23) | `std::is_scoped_enum`

### Possible implementation

    template<typename E>
    struct is_scoped_enum : std::bool_constant<requires
    {
        requires std::is_enum_v<E>;
        requires !std::is_convertible_v<E, std::underlying_type_t<E>>;
    }>
    {};

### Example

Run this code

    #include <type_traits>

    class A {};

    enum E {};

    enum struct Es { oz };

    enum class Ec : int {};

    int main()
    {
        static_assert(std::is_scoped_enum_v<A> == false);
        static_assert(std::is_scoped_enum_v<E> == false);
        static_assert(std::is_scoped_enum_v<Es> == true);
        static_assert(std::is_scoped_enum_v<Ec> == true);
        static_assert(std::is_scoped_enum_v<int> == false);
    }

### See also

is_integral (C++11) | checks if a type is an integral type (class template)
is_arithmetic (C++11) | checks if a type is an arithmetic type (class template)
is_scalar (C++11) | checks if a type is a scalar type (class template)
is_enum (C++11) | checks if a type is an enumeration type (class template)

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